Sorry can't resist, maybe a few tall hair grass plants behind the driftwood on the slope like Eleocharis montevidensis? Then in front of the wood on the slope a small version of Hair grass Eleocharis parvula Moss covered wood? Just a few whips of Eleocharis parvula behind the driftwood on the right side to repeat the planting. leaving the middle open and clear for contrast.
I think I have Tank envy.